1. Field of the Invention
The present invention relates to a switched-capacitor circuit and a pipelined A/D converter configured by using the switched-capacitor circuit.
2. Description of the Related Art
A pipelined A/D converter is well-known as a high-speed A/D converter with high resolution.
Further, a switched-capacitor circuit is in wide use in order to enable the pipelined A/D converter to perform a series of signal processing with a simple circuit and with high accuracy. An example of the switched-capacitor circuit of this kind is disclosed in Japanese Unexamined Patent Application Publication No. 2000-13189.
In conventional switched-capacitor circuits disclosed in the aforesaid patent document and so on, a feedback gain from an output to an input of an amplifier is as small as ½. Therefore, there has been a problem that power consumption of the amplifier becomes relatively large. There has been a problem that reducing power consumption results in a relatively low operating speed of the circuit. There has been another problem of a poor signal-to-noise ratio (SNR) since equivalent input noise of the amplifier is amplified twofold.